A method and an apparatus for digitally and automatically controlling a bias voltage of an electro-optic optical modulator are disclosed. The method includes: outputting a scanning bias voltage; acquiring a first optical signal; converting the first optical signal into a first electrical signal; outputting a first direct current signal; calculating an operating bias voltage at each operating point and a half-wave voltage; calculating an error feedback coefficient and a dither amplitude; outputting an operating bias voltage and a dither signal with the dither amplitude; acquiring a second optical signal; converting the second optical signal into a second electrical signal; outputting a harmonic component; calculating a harmonic amplitude and a shift phase; calculating a new bias voltage; and using the new bias voltage as the operating bias voltage.

A backplane for a communication system having a back-side and an opposite front-side both having traces capable of conducting electrical and/or optical signals that comprises a plurality of layers with traces capable of conducting electrical signals and vias for passing optical signals between said back-side and said opposite front-side. The back side is further provided with optical fibers capable of transporting the optical signals and optical elements affixed on an exit of one via of the plurality of vias in the back-side, wherein each optical element is capable of focusing optical signals coming through the via collimating optical signals from an optical fiber into and through the via to the front side. Systems based on the backplane are provided.

Messages on controller area network (CAN) buses are communicated over subsea links. Messages are sent as electrical or optical signals. The present invention provides a subsea CAN BUS electronic distribution unit (EDU) for transmitting, receiving, converting, and routing electrical or optical signals sent over a subsea CAN BUS network. The CAN BUS EDU of the present invention is contained within a single housing and combines the functions of transmitting, receiving, converting, and routing electrical or optical signals sent over a subsea CAN BUS network that would typically be handled by multiple devices.

Optical transmission systems and methods are disclosed that utilize a QSM optical fiber with a large effective area and that supports only two modes, namely the fundamental mode and one higher-order mode. The optical transmission system includes a transmitter and a receiver optically coupled by an optical fiber link that includes at least one section of the QSM optical fiber. Transmission over optical fiber link gives rise to MPI, which is mitigated using a digital signal processor. The QSM optical fiber is designed to have an amount of DMA that allows for the digital signal processor to have reduced complexity as reflected by a reduced number of filter taps as compared to if the DMA were zero.

Spatial division multiplexing (SDM) allows multiple optical signals to be multiplexed onto a single optical link. Performance of SDM systems may be improved by monitoring performance metrics indicative of crosstalk between the spatially multiplexed signals and adjusting at least one transmission characteristic of one or more of the multiplexed signals in order to reduce the impact of the intermodal crosstalk.

An optical system for coupling an optical signal into an orbital angular momentum (OAM) mode of an OAM optical fiber is disclosed. The system includes a first detector array for capturing an input image, a processor for processing the input image to determine modal purity and for generating a feedback signal based on the modal purity and a spatial light modulator (SLM) having an array of pixels that are adjustable in response to the feedback signal. This system improves modal purity and lessens modal crosstalk.

A system and method are presented for coupling OAM optical beams to optical fibers. The system may include, for instance, an OAM beam generator, for receiving one or more of a plurality of input signals, and generating a different OAM mode signal for each input signal. The OAM beam generator may further be operative to adjust a location and/or an exit angle of the one or more OAM mode signals before sending the one or more OAM mode signals to a beam combiner that combines the one or more OAM mode signals into a combined mode OAM transmission. The system may further include a controller in communication with at least one crosstalk estimate sensor and the at least one OAM beam generator, the controller operative to optimize the crosstalk estimate by receiving the crosstalk estimate for one of the OAM mode signals, and sending control instructions instructing the OAM beam generator to adjust a location and/or an exit angle of the one or more OAM mode signals to reduce the crosstalk estimate.

An optical millimeter wave terahertz transfer system and transfer method are disclosed. The device comprises a local terminal, a transfer link, an access terminal, and a user terminal. By using the device in the transfer link, optical signals transferred forward and backward are extracted through optical couplers, and millimeter wave terahertz signals with a stable phase are obtained at any position in the transfer link through optical signal filtering, photovoltaic conversion, microwave filtering, frequency division and optical frequency shift processing. The device and method have the characteristics of high reliability, simple structure, and low implementation cost.

An optical assembly includes a base plate, a light transmitting component arranged on the base plate, a lens component arranged on the base plate along an optical path of light transmitted from the light transmitting component, a supporting member, and an auxiliary member. The supporting member includes a bottom surface that bonds to the base plate and a side surface that connects to the auxiliary member. The auxiliary member includes a side surface on which the lens component is disposed and a bonding surface that bonds to the side surface of the supporting member. The lens component is configured to focus and couple, or collimate, an optical signal transmitted from the light transmitting component. A bottom surface of the auxiliary member and a bottom surface of the lens component are both higher than the top surface of the base plate.

There is provided an optical communication device as a first optical communication device coupled to a second optical communication device through a plurality of logic links, the optical communication device including a memory, a processor coupled to the memory and the processor configured to generate a first control frame into which each piece of information for indicating an amount of each data to be transmitted to the second optical communication device is allocated in an order corresponding to each identification information of the plurality of logic links, and transmit the first control frame generated by the processor to the second optical communication device by using the plurality of logic links.